This invention pertains to a new and improved device for demonstrating occlusion and the effect thereof on a temporomandibular joint.
Devices of this category are especially useful in demonstrating to those unfamiliar with the field of occulsion and with the operation of a temporomandibular joint the interrelationship between the two. This is especially desirable in explaining the cause or possible cause of many different painful ailments which can result from occlusal problems tending to cause temporomandibular joint dysfunctions. Because of the nature of this invention, it is considered necessary to explain certain terms as are commonly utilized in the dental field as a prelude to explaining the invention itself.
The term "occlusion" as used herein designates the manner in which the teeth fit together within a mouth, as for example, when the jaws of an individual are in a "normal position" in which the teeth on the upper and lower jaws rest against one another. Technically, the upper jaw of an individual is referred to as a maxilla and the teeth located on it are referred to as maxillary teeth. In a corresponding manner, the lower movable jaw is referred to as a mandible and the teeth on it are referred to as mandibulary teeth. The motion of the mandible relative to the maxilla is controlled in part by two joints which are roughly comparable to a common ball and socket joint. Such joints are referred to as temporomandibular joints. Each of such joints includes a socket-like element referred to as a fossa in association with the maxilla and a ball-like element referred to as a condyle associated with the mandible. The condyle fits generally within the fossa in such a manner as to permit several different types of movement of the mandible. One type of such movement is of a rotary character; it involves rotation of the mandible about an axis which is commonly referred to as a hinge axis. The position of this hinge axis can be varied by varying the position of the lower jaw or mandible as, for example, by extending the mandible in a protrusive manner. Normally, the hinge axis is in a so-called centric position corresponding to a position of the mandible in which the teeth on both of the jaws having normal occlusion fit closely so as to be aligned with one another.
When the maxillary and the mandibular teeth are not in a desired or proper relationship to one another as, for example, as a result of malocclusion, normally a person will automatically shift the position of the mandible so as to compensate for the malocclusion of the teeth. In the usual instance, this results in the condyles of a jaw being shifted out of a centric position so that the hinge axis is slightly displaced from its normal location. This temporomandibular joint dysfunction results in a number of different consequences largely relating to the stress or strain associated with various muscles used to support and move the mandible. These may result in ear, head, neck, back, facial and other pains resulting from what may be loosely referred to as jaw or temporomandibular joint "disharmony".
The devices of the present invention are useful in indicating or illustrating how the position of the condyle and of the hinge axis within a temporomandibular joint will vary in accordance with the occlusion within a mouth. This is considered desirable in indicating to a person, such as a patient, suffering from a consequence of malocclusion the probable cause of his or her problem and the need for corrective measures. The devices of the present invention are especially significant in their ability to demonstrate or illustrate how the position of the condyle and a hinge axis may be affected as a result of various different types of occlusal problems. Further, these devices are important as being capable of being used to illustrate in a generalized manner the ways in which splint or jaw repositioning devices may be utilized in the diagnosis and treatment of various types of occlusal problems.
Those in the field of dentistry will, of course, recognize that there have been many different types of devices which are capable of being used to demonstrate both proper and abnormal or undesirable occlusion between maxillary and mandibular teeth and which are capable of being utilized to demonstrate the treatment or correction of undesirable occlusion by various different techniques. In one of these techniques--occlusal equilibration--the mating surfaces of various teeth are reshaped so as to eliminate pressure on certain teeth when the jaws are closed or during common jaw movement such as chewing. Various occlusal problems are, on occasion, resolved through restorative techniques involving the replacement or reconstruction of the individual teeth. Occlusal problems may also be combatted with use of splint or jaw repositioner appliances tending to encourage an individual to hold the mandible so that the condyles carried by it are in a separate position.
Perhaps the most common devices capable of being used to demonstrate both proper and abnormal occlusion and these various different treatment techniques or modalities are dental articulators. In general, common articulators are considered to be too complex and too "technical" to be used in explaining various elementary factors relating to occlusion to those who are untrained in the field of dentistry. Further, in general, common articulators are considered to be undesirably expensive for these purposes, At various times somewhat simplified structures capable of demonstrating normal and abnormal occlusion have been developed primarily as an adjunct to the use of articulators which are somewhat simpler and less expensive than conventional articulators.
One such device of this type is known as a "Gnathokin". It consists of a lower part corresponding to a mandible upon which there is pivotally mounted an upper part corresponding to a maxilla. Both of these parts carry what may be loosely referred to as a "framework;" the positions of these frameworks are capable of being adjusted relative to the parts upon which they were located. Each of them carries various simulated teeth. At least one other device of a substantially similar related character has been developed. It is considered that devices of these categories are undesirable in demonstrating normal occlusion and various types of abnormal or undesirable occlusion because of their relative complexity. This is related to the consideration that a device useful in demonstrating occlusion and problems pertaining to or resulting from malocclusion to those who are untrained in the field of dentistry should be comparatively simple to avoid confusion and also to minimize the cost of the device.